Warp let-off device of a power loom



Nov.. 12, 1957 KYUGORO sAKAMoTo 2,812,389

wARP LET-OFF DEVICE 0F A POWER LOOM 5 Sheets-Sheet l Filed Sept. 26-l 1955 INVENTOR.

-BY WMM,

' AHORA/sysA Nov. 12,. Y1957 KYuGoRo SAKAMOTO 2,812,780

WARP LET-OFF DEVICE OF A POWER LOOM 5 Sheets-Sheet 2 Filed Sept. 26, 1955 K YUGORO SAKAMOTO INVENTOR.

ATTORNE vs Nov. l2, 'i957 KYUGORO sAKAMoTo 2,812,780

WRP LET-OFF DEVICE OF A POWER LOOM Filed sept. 25. 1955 5 sheets-sheet s KYUGoRo 5A KAMoro INVENTOR.

ATToRNErs NGNu l2, 1957 KYUGORO sAKAMoTo 2,812,780*Y WARP LET-OFF DEVICE OF A POWER LOOM Y Filed. Sept. 26. 1955 5 Sheets-Sheet 4 KYUGoRo SAKAMoro INVENTOR.' Y

\- M14/MM, mami ATTORNEYS NOV 12, 1957 KYuGoRo sAKAMo-rc 2,812,780

WARP LET-OFF DEVICE oF A vP owER Loon/1 Filed Slept. 26, 1955 5 Sheets-Sheet 5 KYUGoRo SAKAMoTo INVENTOR.

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United States Patent -WARP LET-OFF DEVICE F APOWERLOOM Kyugoro Sakamoto, Hamamatsu, Japan Application September 26, 1955, Serial.No.l,53l6,l676

Claims priority, application Japan April 9 .@1955` i s claims. (ci. 139-108) i` This invention relates to improvements -in awarp let off device for a power loom, wherein `warp yarns are positively let off at a constant speed by changing the angle of rotation of the warp beam in accordance withthe decrease in the number of layers of warp yarns on the beam.

In the usual loom of this type, the rotation of the yarn beam generally depends upon the tension of `the Warp yarns to be woven, and the yarns are let off at Va-quicker speed when the tens-ion of the yarns becomes larger. But `this let-off means does not give a good result when thin or elastic yarns are woven, because the yarn itself is affected by the tension.

An object of this invention is to provide a let-off device wherein the speed of rotation of the yarn beam depends on the decrease in the number of the yarn layers on the beam, but modified according to a theoretical curve.

Another object of this invention is to provide `means adapted to cc-operate with said let-off device so as to further modify the speed of rotation of the Vbeam due to accidental changes of tension of the yarns. i

A preferred embodiment of the inventionlis.illustrated `in the drawings, wherein:

Fig. 1 is a side elevation of a loom having warp le-toi device according to the present invention; i

Fig. 2 is the same view as that of Fig. 1 on a larger scale, showing the left part of Fig. 1 in-detail;

Fig. 3 is a front view looked from the :leftehand side of Fig. 2; i

Fig. 4 is a plan view of the left part of Fig. l, showing only the upper parts there-of;

Fig. 5 is an elevation taken on line A-.A `of Fig. A2.; and

Fig. 6 is a plan View taken on line B-Bof Fig. 2.

In Fig. l, 1 is the left side frame of the 1oom,.on .which the rocking shaft 2, the tappet shaft 3 and the .crank shaft 6 are held on bearings. The lay sword 5 is .pivoted on the rocking shaft, and is swung `by the crankshaft as usual.

In Figs. 1, 2 and 5, a box 10 is secured to the .inner `side of the side frame, `on which are held .three .spindles 7, 3 and 9, and two arms 11 and 12 are secured to .the spindle 7. The arm 11 is connected to a .pin 14` at the yfoot of the lay sword 5 by a connecting rod V13, so `that the swing motion of the lay sword 5 is transmitted to the arm 12. On the spindle 8 are secured arms .15 and l16, the former extending forward and the `latter downward. The arms l?, and 15 have respectively a slot 12and 15' along their length, and these slots are almost overlapped.

The arm 16 is fixed at the outer end of thetspindle 8 and has also a slot 16 along its length, and a scale 9.0 is provided along the edge of the slot.

A presser shaft is designated by reference numeral 117 and a presser arm 19 is fixed to the shaft, which is forced toV turn in the direction zz by a spring `1,8 wound o n lthe shaft.

Another arm Ztl is securedto the shaft 17. l,On Athein- ,side of the im to is provided a slid-ing .plate y21 which` .aan be slid .in .a sudagraovefin the wall .Of all@ haal." .e

2,812,780 tened Nov. 1.2.1957

-pinfl22hprovided `at the front end of the sliding plate 4is Yconnected to-a pin 92 at the end ofthe arnrn` 20 by a link y23, so tthatfthe platetis pulled by `thearm 20 when the `pressen-arm 19is turned. A curved groove 24 is pro- -vided-in the slidingplate 21, `the profile of the groove .beilng I.made :in theform which is approximately a parabo a. t i

An. arm 25 is pivoted on `apin 9, and an idle roller 27 .on a .pin 26, whichisprovided on the arm 25, is tted :inathe vgroot/e241.' Thefront part of the arm 25 is `bifurcated, andaslot `25'.is .made -in that part. Thearm 12 and 15 are located between the bifurcated arms andan :idle roller 28 passesthrough a hole which is formed .at .the .crossing point ...of the three slots 12, 15', and 25. YOn,ac`count.of. this connection, when the arm 12 is rocked .through an. angle, ,the arm 15 `is also rocked lthroughthe intermediary `of the .rollert28, but the rocking angle of :the arm 15 `variesaccordingto the position of the roller, while thatof .the arm .11 is constant.

'.Whentthe vpresser shoe 91 turns .in the direction a due ,to decreasef .the .number of the yarn layers and the consequent decrease in thediameter of the roll of yarns, the sliding, platet21is slidin the direction b by the arm 20 .$0 ;.that the rarm :25 .turnsin the direction c as the roller .2 7 isgraisedalong the groove 24, and the rocking angle of the arm 15 gradually .increases While the arm 12 is rocking in a definite angle.

A ,Weight lever 29 `is secured toashaft 30` on each side Aof the loom, A weight 31 .ishung at the free end of the Jever, and the upper end of the lever is connected by ,a .leger 8,010 aflink 81 on which a tension pulley 84 is mounted, that the tension `of the `.warp yarns 102 is attested 'by the Weight :as .hereinafter ,describediA.slideqbar353 ,is connected Ato the ,weightilever on the deft e. Japin 9.3 by an adjustable rod 32 providing Vwith a tl n buckle The bar 33 is slidably fitted in a tenida .-3. @Kai :to ,the frame f Twp V arms v13,6 and 37 vare Isecured .to Va pin 35 at the lower Hend ,of the slide bar Q3. The lower end `of the arm 37 is connected by a rod 39 to a pin 3S, which is fitted virrthe "slot 16' kand `is adjustable in position along .th=1, t(k yig. 2). l"llhe 36lhals a slot 36 and a roller ,42'jistrotatablydittedintheslot. The roller is provided at th eattemaend Qfa teckel, whihiss1idab1y-tfd in a and@ 4.0.16@ tO- .the frame "Theracklmeshes with am# f5.0, a .Shaft @lasers 9.5 4and V9.6 (Fie 3) iA `ratchet `wheel 5,1 .is horizontally ixed on the shaft 43 at its lowerend, .and Tpawls `53 are .pivoted on afanshape `plate 52, which .is extended .from `the boss `of the sector 1M. An karm 5.4 is loosely lixed to `the shaft `.43, .and acm-.ved plate 55 `fixed a-tkthe end .of the arm extends AClose ,to the ,periphery of the ratchet :wheel 51.

,Thearrn `5,4 has a`rearward `extension 54', and is connectedtoa rod ub y a ,pin 57. A bracket 59 is mounted on the frame. L t A `The rod 58 ,isieonneeted to a foot lever97 pivoted at the front ,side of :the loom, Aso .that `the .trod 58 `is pulled indire direction d if an ,operator treads` on the -foot lever, and ,the tcurved plate y55, is `turned in the direction ve and enters .into ,the .fs-pace between the ratchet wheel and the pawls', in ,order Ato disengage the latter from the .ratchet wheel i .t thilppafead af the ;shaf is laoselritfeda gear 50,. which @aube turned Aby .a gear 64,011@ vertical "Shaft ,ig. 2.).A A skew gear .fixed on .the `shaft 98, andrea@ ,be `anni ...by a :handle 97.9 in .front 0f the 1.09m .le 6.1 and aneksw eraf f6.2., .which .meshes A clutch piece 65 is slidably but non-rotatably fixed by a key on the shaft 43, and can be coupled with a clutch piece 66 provided on the boss of the gear 60. The piece 65 is held by a forked end of a bell-crank 68 pivoted on the frame by a pin 67, so that the clutch piece 65 couples with the piece 66 when the lower end of the bell crank is pulled in the direction f. The upper end of the bell crank is normally raised by the spring 69, so that the clutch pieces Vare uncoupled and the gear 60 is loosely turned on the shaft 43. A piece 70 is fixed at the end of the bar 58, and the lower end of the bell crank 68 is inserted in an `opening in the piece 70, so ythat when the bar 58 is pulled in the direction d, the bell crank is pulled in the direction and the clutch piece 65 is coupled to the clutch piece 66.

On the tappet shaft 3 are provided two cams 71 and 72, and idle rollers 73 and 74 are respectively in Contact with the cams 71 and 72. (Fig. 2). The roller 73 is provided at the end of a lever 75 which is pivoted on a bracket 76 of the right side frame 1 by a pin 100. VThe roller 74 is provided at the lower end of an easying lever 77 which is pivoted on each side of the frame by a stay bolt 78. A roller 79 is held at the upper end of the easying lever 77 so that the roller 79 moves to and fro when the lever is rocked by the cam 72.

The upper arm Z9 of the weight lever 29 is connected by a pin 101 to the link 80, which in turn is connected to the lever 81 on each side of the frame as already described. A pair of guide rollers 85 are mounted on the bracket.

An arm 86 is rigidly secured to the Shaft 30 (Figs. l, 2 and 4), and a brake shoe 87 is provided at the free end of the arm. A -cylindrical recess is provided in the arm 75 and a piston 88 is slidably fitted therein. Through the piston is extended a bolt 89, and the latter is fixed to the piston at its head, and a spring 90 is provided in the piston pressing the piston head against the brake shoe 87. The pressure of the piston against the shoe can be adjusted by lock nuts 91 fixed on the bolt. As the weight lever 29 is rigidly connected to the arm 86 through the shaft 30, the influence of the weight 31 on the lever 29 is inactive when the shoe 87 is braked by the piston 88.

The `operation of this novel loom is as follows.

The lay i-s swung by the rotation of the crank shaft 6 `as usual, and the arms and 16 are rocked through a certain angle according to the position of the roller 28. By adjusting the position of the pin 38, the stroke of the rod 39 can be regulated.

The rocking motion of the arms 37 and 36 slide the rack 41 and turns the ratchet wheel 51 through the sector 44, plate 52 and the pawls 53. The rotation of the ratchet wheel turns the warp yarn beam through the worm gears 45 and 48, spur gears 49, 50, 95 and 96, therefore the warp yarn is positively let oft.

While the diameter of the beam yarn is decreased, the presser arm 19 moves in the direction a, and the sliding plate 21 moves inthe direction b, so that the arm 25 turns in the direction c by the co-operation of the curved groove 24 and the roller 27. By this means, the 'roller 28 gradually approaches to the spindle .8, and the rocking angle of the arms 16 increases. l

If the tension of the warp 'yarn 102 accidentally increases, the tension roller 84 is compelled to move right# ward in Fig. l, so that the weight lever 29 turns in the clockwise direction on its pivot, and the rod 32 is raised. While the roller 42 stays at a definite position, the arm 36 raises so as to increase the distance between the pin and the roller 42, so Vthat the travel of the rack 41 is increased while the rocking angle' of the arm 37 'is substantially unaltered. `If the travel of the rack is increased, the angle of rotation of the sector 44 is increased, so that the rotating angle of the ratchetkwheel 51. is increased. By this means the rotation of the yarn beamV isY increased, and the tension of the warp yarn is moderated.

On the contrary, if the tension of the warpyarn is rack 41 is decreased so that the speed of rotation of the ratchet wheel is decreased and the normal tension of lthe yarn is recovered. l e

When the loom is not in operation, the yarn beam can be turned by a handle. yIn such a case the` foot lever 97 is trod, and the arm 54 is turned in the direction e, and the plate disengages the pawls from the ratchet wheel allowing the latter to be freely turned. At the same time, the piece pulls the lower end of the lever 68 in the direction j, so that the clutch piece 65 is coupled with the piece 66. Then the handle 99 can be turned in any required direction, and the vertical shaft 43 is turned through the worm gear 62 and 63. Thus, the yarn beam can be turned in any direction.

When the yoperation of the loom stops, the crank pin 1,03 always takes the position, due to balance of the working parts, at an angle of about degrees on the upper part of the circle. In case the crank pin is in this area, the cam 71 takes the position which enables it to brake the arm 86, so that the yarns on the tension roller 84V are not affected by the weight 31, while the loom is not in operation.

The length of yarn to be let ot during one rocking motion of the lay can be adjusted by changing the position of the pin 38. To facilitate the adjustment, the scale is kprovided along the edge of the slot 16.

According to this invention, the rotation of the yarn beam iseiected by the rocking motion of the lay, and the angular velocity of the yarn beam gradually increases while the number of the layers on the beam, and thus the diameter of the beam, decreases. This change of angular velocity is determined by the rising speed of the pin 28 along the arm 12, and its rising speed is controlled by the curved groove 25. Therefore the let olf speed of the warp yarn can be maintained constant throughout the operation if the profile of the curved groove is made in the form of which is approximately a parabola. If an undue tension on the warp yarns for any reason, the travel of the rack 41 is automatically increased or decreased by the motion of the weight lever, and the speed of rotation of the ratchet wheel is increased or decreased so that the normal tension of the warp yarns is recovered.

What I claim is:

1. A warp let-oh` /device for a power loom having a loom lay, a yarn beam, and a weight lever carrying a weight for tensioning the warp yarn, said device comprising three arms each pivoted on the loom and each having a slot therein, said arms being crossed at a common crossing point, a pin through said slots at the common crossing point, the first of said arms being connected to the loom lay for receiving the rocking movement of the lay, a plurality of pawls pivoted on the loom to which the second of said arms is connected, a ratchet wheel on the loom engageable by said pawls for driving the yarn beam on the loom, a member having a curved slot therein movably mounted on the loom, a roller on the third of said arms engaged in said curved slot, and a presser shaft pivoted on the loom with one end connected to said member and the other end pressing on the yarn beam, whereby a change in diameter of the yarn beam permits the presser shaft to pivot and move said member, thus moving said third arm.

2. A warp let-off device as claimed in claim l in which the connection of the second of said arms to said pawls comprises a slide bar connected at one end to the weight lever, the other end of said slide bar having two extensions thereon, a connecting rod connecting one of said extensions to the second of said arms, a rack connected to the other of said extensions, and a gear sector on which said pawls are carried pivoted on said loom concentric with Vsaid ratchet wheel and engaging said rack.

3. A warp let-ofi? device as claimed in claim l in which 'said member having the curved slot therein is a plate slidably mounted -on said loom, said plate being connected to said presser shaft by a link pivoted to said plate and secured to said presser shaft.

4. A Warp let-01T device as claimed in claim 1 in which said curved slot has a curve approximating a parabola.

5. A warp let-off device as claimed in claim 1 further comprising an arm pivoted on said loom, an idler roller at the free end of said arm, a tappet shaft rotatably mounted on the loom, a cam on said tappet shaft on which said idler roller rolls, said arm having a cylinder therein, a resilient piston in said cylinder, a post on the Weight lever at the fulcrum thereof, a brake shoe on the end of said post against which the head of said piston bears,

whereby when said cam lifts said arm, said piston bears on said brake shoe to brake the pivoting of the weight lever.

References Cited in the le of this patent UNITED STATES PATENTS 2,609,006 Lord Sept. 2, 1952 2,609,007 Beall Sept. 2, 1952 FOREIGN PATENTS 869,775 Germany Mar. 9, 1953 

